1. Field of the Invention
This invention relates to mono- and diglyceride emulsifier compositions obtained by the interesterification or glycerolysis of triglycerides with glycerol. When a triglyceride is reacted with glycerol at high temperatures, for example 200-250° C. under alkaline catalysis, a mixture of mono-, di-, and triglycerides is produced, with a small proportion of unreacted glycerol remaining. Commercial mono- and diglycerides usually contain 40-55% monoglycerides, 38-45% diglycerides, 8-12% triglycerides, and 1-7% free glycerol.
In accordance with this invention, the diglyceride portion w/w is increased to a level of at least about 65% to about 80%, more preferably from about 70 to at least about 80%, and most preferably about 74%, for example, by vacuum distillation, with the remaining monoglyceride portion being about 10% and the triglyceride portion of the order of 15%. Alternatively, a glycerine to fat ratio is selected to yield the required elevated diglyceride portion.
The high diglyceride emulsifier (herein “HiDi”) has a number of uses, including structuring of a non-hydrogenated vegetable oil based shortening for food products such as bakery goods, which have significantly lower saturated fat content and a substantially higher polyunsaturated fat level than has heretofore been available with conventional mono- and diglyceride emulsifiers.
2. Description of the Prior Art
A number of food products, especially baked products such as bread, cakes and other pastries, icings, and the like, require the inclusion of fat-continuous emulsions such as shortenings and margarines. It is necessary for certain food applications that the shortenings or margarines have specific structural characteristics, such as plasticity, dispersibility, and solid fat content profile, i.e., the percent solid fat present at different temperatures.
In the past natural products such as butter or lard were used in food applications that required a plastic fat. For a number of reasons including availability and cost, shortenings and margarines have more recently been produced from vegetable oils. Since vegetable oils are liquids, they must be given structure by the introduction of solid fat in order to achieve the desired plasticity and solid fat content profile required for functionality. A number of approaches have been employed for generating the solid fatty materials needed to achieve the desired solid fat content profile for the particular temperatures required in a food processing operation. Two approaches that have been widely practiced in the past involved the partial hydrogenation of the vegetable oil, and/or the addition of solid fatty materials. Oil and solid fat blends can be interesterified to further improve functionality. When a solid fatty material is added, that material can be obtained either by hydrogenation of a fat or oil or by fractionation of solid fat from a naturally occurring fat. These approaches are well known among those skilled in the art of preparing fat-continuous emulsions such as shortenings and margarines.
The structured fats used in the production of fat-continuous emulsions contain saturated fatty acids and unsaturated fatty acids. Naturally occurring unsaturated fatty acids have carbon-carbon double bonds in a cis-configuration. Partial hydrogenation of fat can cause isomerization with some of the carbon-carbon double bonds of the cis-unsaturated fatty acids being converted to the trans-configuration. Until recently, trans fatty acids were nutritionally categorized along with cis fatty acids as unsaturated fatty acids without the demonstrated negative health consequences of saturated fatty acids. However, a great deal of research has recently implicated trans fat in the development of cardiovascular disease. Thus, the National Academy of Medicine and many nutritionists have advised that consumption of trans fats be limited as much as possible within the needs of a nutritionally adequate diet. Minimizing the presence of trans fatty acids in the diet requires that the efficient and economically advantageous practice of partial hydrogenation be eliminated or at least greatly reduced. Therefore, there is a need for alternative approaches that will permit the structuring of fats for use in fat-continuous emulsions such as shortenings and margarines without introduction of trans fatty acids or increase of the saturated fatty acid content.